feat: add request retry

Author: chachaxw

js/request_retry.js

@@ -0,0 +1,41 @@
+function requestWithRetry1(url, attempts = 3) {
+    return new Promise(function (resolve, reject) {
+        fetch(url)
+            .then(function (result) {
+                resolve(result);
+            })
+            .catch(function (error) {
+                attempts--; // 2, 1, 0
+
+                if (attempts === 0) {
+                    reject(error);
+                } else {
+                    setTimeout(() => {
+                        requestWithRetry1(url, attempts);
+                    }, 3000);
+                }
+            });
+    });
+}
+
+async function requestWithRetry2(url, attempts = 3) {
+    const retry = async (attempt = 1) => {
+        try {
+            return await fetch(url);
+        } catch (error) {
+            if (attempt >= attempts) {
+                throw error;
+            }
+
+            // Use an increasing delay to prevent flodding the
+            // server with requests in case of a short downtime.
+            const delay = 1000 * attempt;
+
+            return new Promise((resolve) =>
+                setTimeout(() => resolve(retry(attempt + 1)), delay)
+            );
+        }
+    };
+
+    return retry;
+}